CHANGES IN MUSCLE PROPERTIES DURING POSTMORTEM STORAGE OF FARMED SEA BREAM (SPARUS AURATA)

Abstract

This study assesses the effects of storage temperature on postmortem changes in textural parameters (firmness, water holding capacity), and their relationship with biochemical and electrophoretic determinations (muscle collagen content and solubility, amount and integrity of sarcoplasmic and myofibrillar proteins) in sea bream muscle. Storage at 1C resulted in a prolongation of the firmness compared with 4C, with no noticeable changes in water holding capacity. This delay in muscle softening at 1C could be partially explained by a limited proteolysis of some myofibrillar proteins, although inconsistent tendency was observed for other fractions. In contrast, the rate of muscle collagen degradation was higher at 4C compared with 1C, this becoming the main contributing factor to firmness losses. The great variety of protein fractions separated electrophoretically, and the relatively minor and contradictory changes observed suggest the unfeasibility of electrophoresis as a routine procedure for studying freshness in stored sea bream. PRACTICAL APPLICATIONS According to the results obtained, it is strongly recommended that the storage of sea bream (Sparus aurata) throughout the commercial chain is carried out at 1C, instead of the usual temperature of 4C. This modification clearly delays the process of muscle softening, thus improving objective quality in this species. The electrophoretic separation of muscle proteins has been previously proposed as a suitable procedure for assessing the freshness of fish during cold storage. However, the results obtained here indicate that the attempts aimed to the development of an electrophoretic procedure for detecting modifications in muscle proteins that could be correlated with flesh textural properties were unsuccessful. This is especially true if short‐term deterioration is assessed.

Post-Mortem Changes of Silver Carp (Hypophthalmichthys Molitrix) Stored at 0°C Assessed by Electrical Conductivity

“…[21] An increase of WHC was observed during the first 4 h at 0 • C, and then decreased from 67.27% at 4 h to 49.42% at 72 h. According to Nguyen et al, [22] the decreased WHC was probably due to the water loss from muscle fiber driven by protein denaturation. The result also indicated that the change of WHC within postmortem process was in accordance with the change of texture parameters ( Table 1).…”

“…A large variation in the biochemical process was observed during rigor period. [21] The progressive denaturation and hydrolysis of myofibrillar proteins had a negative effect on the toughness of post-mortem fish. Therefore, rigor mortis process affected the texture such as hardness, gumminess, springiness, cohesiveness and resilience (Table 1).…”

“…[23,24] The changes detected in WHC during storage could be explained by the changes of SPP. [1,21] Changes in EC Early Post-Mortem Time EC can be used to determine body-fluid balance and meat quality due to the muscle tissues getting too decomposed and fluids flowing out during storage. The initial EC value was 980.00 µs/cm (Fig.…”

Effect of lightly salt and sucrose on rigor mortis changes in silver carp (Hypophthalmichthys molitrix) stored at 4°C

“…Water holding capacity (WHC) was determined according to Suárez et al . () with some modifications. A fish sample (2 g) was placed in a centrifuge tube that contained tissue paper to absorb water and then centrifuged for 10 min at 1590 × g .…”

PARTIAL CHARACTERIZATION OF GELATINOLYTIC PROTEINASES FROM THE SKELETAL MUSCLE OF GRASS CARP (CTENOPHARYNGODON IDELLUS)

“…2005). Suárez et al . (2005, 2009) reported that initial total collagen content, acid‐soluble collagen (ASC) and insoluble collagen (ISC) of sea bream decreased throughout the storage period at 4C and 1C, and storage at 1C kept the initial amount of ASC and ISC for a longer period than storage at 4C.…”